1. Field of Invention
The present invention relates to a Micro-Electro-Mechanical System (MEMS) microphone device and its manufacturing method.
2. Description of Related Art
FIG. 1 shows a MEMS microphone device 10 disclosed in U.S. publication No. 2008/0175418. As shown in FIG. 1, the MEMS microphone device 10 includes: a substrate 11, a back-plate 12, a flexible diaphragm 13, through-holes 14, backside cavity 15, and a stationary portion 16. In one embodiment, the flexible diaphragm 13 may include a material of, for example, polysilicon, and the back-plate 12 may include a material of, for example, single crystal silicon. The back-plate 12 has the through-holes 14 communicating with the backside cavity 15, and the flexible diaphragm 13 is connected with the stationary portion 16 by springs. When a voice signal vibrates the flexible diaphragm 13, a capacitance is changed accordingly. Then, the changed capacitance is converted to an electronic signal by a circuit. In this prior art, the MEMS microphone device 10 still requires a series of complicated package processes so that a product having the MEMS microphone device 10 requires a large area and is difficult to shrink.
In addition, similar to the U.S. publication No. 2008/0175418, the MEMS microphone devices disclosed in U.S. publication No. 2008/0175418, U.S. publication No. US 2008/0175418 and U.S. Pat. No. 7,221,767 also require a series of complicated package processes so that a product having one of the MEMS microphone devices requires a large area and is difficult to shrink.
In the view of above, to overcome the drawback in the prior art, the present invention proposes a MEMS microphone device and its manufacturing method which improve wafer-level manufacturing process to simplify package process and save room so that the whole device can achieve chip size package (CSP).